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dr wogz

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Hi all,

With advent & popularity of 3D printers, many are now starting to look at designing their own parts & creations. And, with more & more "entry level" CAD programs out there, it's just getting easier to design & develop your own designs.

But using a CAD program, thinking in 3D, understanding the features, functions, and buttons can be intimidating!

So, let's start a list of ideas & thoughts we have that make our design easy, thoughtful, and generally pain free to modify / manipulate..
 

dr wogz

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Be mindful of your start orientation / work-plane selection.

All CAD program have three planes on which you can start your model. Use them wisely. It can also make it less of a hassle when importing your model into your slicer, as it imports 'the right way up'. (Or imports so that you don't need to spin it on 1 or 2 axis..) As well as with drawing creation (if you go that far, to create drawings of your parts..)

When you build a house, you start of the ground, the XY plane, and build up. But building a house in CAD (or at least, to extrude the house shape) you might want to start of the ZY plane and extrude it thru the X direction. This way, your house is oriented 'right side up' but you started on a vertical "right-side" plane..

The same with your Models. Build them "the right way up". I have an idea of what my part is going to look like. (I know how my printer prints.) When I start building my part in CAD land, I'll start on one of the three planes that makes the most sense for the part to be oriented properly.. Sometimes you might even want to create a new work plane on which to start your model, so that it ends up 'right side up'. Then, the part is always 'right side up'.

(The number of times I've started a model, or use a co-worker's model that isn't 'right way up' is .. well.. A little forethought on how you start can go a long way!)
 

cwbullet

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Added this to the sticky list.
 

Chad

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when you say "extrude" it sounds like SketchUp, is that what you use? I use LibreCAD for 2d drawings, it has some support for an isometric view.
 

dr wogz

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I (currently) use Creo 3 (PTC / Pro Engineer). I have used Inventor & mechanical Desktop in past jobs. (as well as very short stint (1999) with Cadkey) I have over 20 years in front of a 3D parametric CAD station, and over 30 years in drafting & design. I'll also toss in 20 years of technical writing and technical illustration.

I will be listing a 'term definition' soon, as they pretty much all work the same way..

But yes, Extrude is just that: push a 2D shape thru an axis perpendicular to the 2D plane at a set amount..
 

dr wogz

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Modelling & the model tree: Keep things simple!

Simple modelling, many steps make light work. When you’re modelling your part, don’t try to do the whole thing in one sketch.. Keep the geometries simple. If you’re modelling a square with mickey mouse ears (a circle at each corner). Make it so. A square, then add the circles. Editing, refining, or trouble shooting your design later will be much easier. Some modellers allow you to rename the geometries in the modelling tree. Do so, it’ll be much easier to navigate and edit the part later..
 

dr wogz

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Fillets & Chamfers.

Most decent modellers will have a fillet and a chamfer tool. You pick an edge, ant it’ll give you a radius for a fillet or as for the depth for a chamfer (or ask for the X and Y for an unequal chamfered edge.)

Always try to put your fillets & chamfers at the end of the design cycle. This make it easier to edit the part later. And, doing makes the model less likely to crash or become corrupt.
 

dr wogz

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The power or parametric

"Parametric" para = many. Metric= value/variable

Many of the new 3D modellers are ‘parametric modellers. Meaning you assign values to give the model form. You can also go farther and give relationships / equations to your measurements. This can allow geometry to remain the same when a value changes. Supposed you have a hole 1/3 the way along on the side of a block. Your block side will be D1 long by D2 high. You hole can be =D1/3 by D2/2. This way, regardless of what your D1 & D2 values are (the side of your block), the hole will always be 1/3 along, and ½ the height. There is usually a switch to turn on & off the variables, so you can build equations.

With this, you can build something, say a NC, whereas all the dimensions are based off one value, the inner BT diameter.

The more advanced modellers (Fusion 360, Solidworks, etc..) you can build parts form tables; an excel file, whereas all the dimension are listed & read from a spreadsheet. This can help with making equations, and you can see all the variables in one place. You just have to remember which variable is which!

You could build a fin can, and have only 4 variables: BT dia, Fin root dim, Fin tip dim, sweep angle (fin rake), and number of fins around. It would calculate it all for you based on these 4 parameters..

You can then start to really think about your design, and start assigning some rules to all this, to have a really robust design.
 

RocketNut9

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I use Alibre CAD program. It is very powerful and very easy to learn and use. There Atom version is there cheatist version but still packs a lot of power CADing power.
 
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